Current File : /var/www/html/node_modules/tsconfig-paths/src/try-path.ts
import * as path from "path";
import { MappingEntry } from "./mapping-entry";
import { dirname } from "path";
import { removeExtension } from "./filesystem";
export interface TryPath {
readonly type: "file" | "extension" | "index" | "package";
readonly path: string;
}
/**
* Builds a list of all physical paths to try by:
* 1. Check for file named exactly as request.
* 2. Check for files named as request ending in any of the extensions.
* 3. Check for file specified in package.json's main property.
* 4. Check for files named as request ending in "index" with any of the extensions.
*/
export function getPathsToTry(
extensions: ReadonlyArray<string>,
absolutePathMappings: ReadonlyArray<MappingEntry>,
requestedModule: string
): ReadonlyArray<TryPath> | undefined {
if (
!absolutePathMappings ||
!requestedModule ||
requestedModule[0] === "." ||
requestedModule[0] === path.sep
) {
return undefined;
}
const pathsToTry: Array<TryPath> = [];
for (const entry of absolutePathMappings) {
const starMatch =
entry.pattern === requestedModule
? ""
: matchStar(entry.pattern, requestedModule);
if (starMatch !== undefined) {
for (const physicalPathPattern of entry.paths) {
const physicalPath = physicalPathPattern.replace("*", starMatch);
pathsToTry.push({ type: "file", path: physicalPath });
pathsToTry.push(
...extensions.map(
(e) => ({ type: "extension", path: physicalPath + e } as TryPath)
)
);
pathsToTry.push({
type: "package",
path: path.join(physicalPath, "/package.json"),
});
const indexPath = path.join(physicalPath, "/index");
pathsToTry.push(
...extensions.map(
(e) => ({ type: "index", path: indexPath + e } as TryPath)
)
);
}
}
}
return pathsToTry.length === 0 ? undefined : pathsToTry;
}
// Not sure why we don't just return the full found path?
export function getStrippedPath(tryPath: TryPath): string {
return tryPath.type === "index"
? dirname(tryPath.path)
: tryPath.type === "file"
? tryPath.path
: tryPath.type === "extension"
? removeExtension(tryPath.path)
: tryPath.type === "package"
? tryPath.path
: exhaustiveTypeException(tryPath.type);
}
export function exhaustiveTypeException(check: never): never {
throw new Error(`Unknown type ${check}`);
}
/**
* Matches pattern with a single star against search.
* Star must match at least one character to be considered a match.
* @param patttern for example "foo*"
* @param search for example "fooawesomebar"
* @returns the part of search that * matches, or undefined if no match.
*/
function matchStar(pattern: string, search: string): string | undefined {
if (search.length < pattern.length) {
return undefined;
}
if (pattern === "*") {
return search;
}
const star = pattern.indexOf("*");
if (star === -1) {
return undefined;
}
const part1 = pattern.substring(0, star);
const part2 = pattern.substring(star + 1);
if (search.substr(0, star) !== part1) {
return undefined;
}
if (search.substr(search.length - part2.length) !== part2) {
return undefined;
}
return search.substr(star, search.length - part2.length);
}
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